Answer
The IUPAC name of the compound is $3-phenylpropanoic \hspace1mm acid$. The common name of the compound is $β-phenylpropionic \hspace1mm acid$
Work Step by Step
The acid has 3 carbon atoms in its longest carbon chain containing the carboxylic functional group. It has a $phenyl$ substituent at position 3. So, the IUPAC name of the compound is $3-phenylpropanoic \hspace1mm acid$. The common name of the compound is $β-phenylpropionic \hspace1mm acid$